The invention relates to a method for packing a catalyst and a device therefor. More specifically, the invention relates to a method for packing a catalyst quickly and uniformly in the space formed between the inner wall of a reactor in which a plural number of reaction tube(s), cooling tubes, heating tubes or combinations thereof are provided, and the outer walls of the tubes, and a device therefor.
As illustrated in ammonia synthesis reactors, methanol synthesis reactors and the like, there are a variety of synthesis processes in each of which a catalyst is filled in a plural number of reaction tubes arranged in the reactor to obtain a desired product. In these processes, various methods are devised to fill the catalyst in the inside of the reaction tubes. An example teaches that a given amount of a catalyst is put in, what is called, a sock having a function capable of opening at the tip, the sock being then inserted into each reaction tube, and the tip of the sock is opened at an appropriate position in the tube to fill the catalyst therein (referred to as the sock method hereunder). In this method, however, prior to filling the catalyst in the sock, it is necessary to measure each time the amount of the catalyst to be packed in the reaction tube to prepare the sock so that it may be inserted into the reaction tube. Accordingly, the sock method takes too much time to be said suitable.
As another method for filling a catalyst in the inside of reaction tubes, the Norsk Hydro method is disclosed in Ammonia Plant Safety, vol. 133, p 18. FIG. 11 is a schematic diagram showing an embodiment thereof. The method aims at packing a catalyst in the inside of a reaction tube. In FIG. 11, a catalyst packing device 60 composed of a jig 70 equipped with brushes 80 and a lead-in pipe 90 for introducing a catalyst 5 is provided on a fixed reaction tube 20. The jig 70 equipped with the brushes 80 is inserted, while being rotated, into the reaction tube 20 to regulate the falling speed of the catalyst 5 sent from the lead-in pipe 90 by means of the brushes 80 thereby to absorb the impact. of the falling. Thus the catalyst 5 is allowed to fall down at a given position in the reaction tube 20 so that it may be packed therein. The reaction tube preferably has at least a diameter equivalent to the total size of several pieces of the catalyst 5. However, the catalyst 5 is uniformly packed by this method on the whole, even though the diameter is not so large as described above.
Aside from the processes for filling a catalyst in the inside of reaction tubes as described above, there is a process for filling a catalyst in the outside of tubes. In this process, in a reactor in which a plural number of reaction tube(s) and cooling tubes or reaction tube(s) and heating tubes are provided, a catalyst is packed uniformly in the space formed by the inner wall of the reactor and the outer walls of the reaction tube(s) and the other tubes. The reactor formerly disclosed by the applicant:in Japanese Patent Laid-Open No. 149640/1980 is an example of the latter process.
In the aforesaid reactor in which a plurality of tubes including reaction tube(s) and cooling tubes or reaction tube(s) and heating tubes are provided, the method for packing a catalyst according to the abovementioned Norsk Hydro method is effective as one of the processes for filling a catalyst in the inside of the reaction tubes. However, the method is not adequate for filling a catalyst uniformly in the space formed by the inner wall of the reactor and the outer walls of the tubes.
To fill a catalyst in the space described above, the sock method has been used, although it takes too much time and labor, because there is no other suitable packing method available.
As described above, in a reactor in which a plural number of tubes are provided, it has been expected to propose a method for packing a catalyst quickly and uniformly in the space formed by the inner wall of the: reactor and the outer walls of the tubes, and a device therefor.
It is an object of the present invention to provide a method for packing a catalyst uniformly and quickly in the space formed by the inner wall of a reactor and the outer walls of tubes, in the reactor in which a plurality of the tubes are provided, and a device therefor.
The inventors have made intensive investigation to solve the above described problems. As a result, it has been found that, in filling uniformly a catalyst in the space formed by the inner wall of a reactor and the outer walls of tubes, in the reactor in which a plural number of the tubes are provided,
(1) the catalyst is passed through a flexible tube, arranged in the inside of the reactor and having a means to absorb the impact to the catalyst, and then fed along the inner wall of the reactor with the falling distance of the catalyst maintained within a certain range so that the catalyst is piled in the space,
(2) the catalyst thus-piled at an angle exceeding its angle of repose flows out spontaneously to cover the bottom of the reactor so that it is packed ununiformly but over the whole area of the bottom of the reactor,
(3) the catalyst ununiformly packed in this way is made uniform by fluidization,
(4) no catalyst collapses by proper selection of the conditions for the packing method and the fluidization, and
(5) the packing time is extremely reduced.
The present invention has been devised in view of the aforesaid circumstances, and the object of the invention is achieved by the method and device described hereinbelow.
In a method for packing a catalyst comprising filling the catalyst in the space formed by the inner wall of a reactor and the outer walls of tubes, in the reactor in which a plural number of at least one kind of the tubes selected from the group consisting of reaction tube(s), cooling tubes and heating tubes are provided, the steps of packing the catalyst in said space by passing the catalyst through a flexible tube arranged in the inside of the reactor and having a means to absorb the immpact to the catalyst and thereby feeding the catalyst along the inner wall of the reactor while maintaining the falling distance of the catalyst within a certain range so that the catalyst may not be broken, and of fluidizing the catalyst thus-packed in said space.
A device for packing a catalyst in the space formed by the inner wall of a reactor and the outer walls of tubes, in the reactor in which a plural number of at least one kind of the tubes selected from the group consisting of reaction tube(s), cooling tubes and heating tubes are provided, comprising a means for packing the catalyst in said space by passing the catalyst through a flexible tube arranged in the inside of the reactor and having a means to absorb the impact to the catalyst and thereby feeding the catalyst along the inner wall of the reactor while maintaining the falling distance of the catalyst within a certain range so that the catalyst may not be broken, and a means for fluidizing the catalyst thus-packed in said space.